Both pharmacy and medicine, since the beginning of antiquity, sought a drug delivery system for the controlled administration of a beneficial drug to a warm-blooded animal. The first written reference to a drug delivery system, a dosage form, is in the Eber Papyrus, written about 1552 B.C. The Eber Papyrus mentions dosage forms such as anal suppositories, vaginal pessaries, ointments, oral pill formulations, and other dosage preparations. About 2500 years passed without any advance in dosage form development, until the Arab physician Rhazes, 865-925 A.D., invented the coated pill. About a century later the Persian Avicenna, 980-1037 A.D., coated pills with gold or silver for increasing patient acceptability and for enhancing the effectiveness of the drug. Also, around this time the first tablet was described in Arabian manuscripts written by Al-Zahrawi, 936-1009 A.D. The manuscripts described a tablet formed from the hollow impressions in two matched-facing tablet molds. Pharmacy and medicine waited about 800 years for the next innovation in dosage forms, when in 1883 Mothes invented the capsule for administering drug. The next quantum and profound leap in dosage forms came in 1972 with the invention of the osmotic delivery device by inventors Theeuwes and Higuchi. This unique osmotic delivery device is manufactured in one embodiment for oral use, and in this embodiment it embraces the appearance of a tablet with an osmotically calibrated drug delivery portal. It is the first oral dosage form in the history of pharmacy and medicine that delivers a known amount of drug per unit time at a controlled rate of delivery throughout the entire gastrointestinal tract. The oral osmotic device maintains its physical and chemical integrity during the prolonged period of time it transits the total length of the gastrointestinal tract.
The oral route is the most ancient route of drug administration, and it is the most convenient route for admitting a drug into the gastrointestinal tract for producing a local or a systemic effect. The oral route can be used for administering drugs that are used topically or absorbed into the systemic circulation from all regions of the gastrointestinal tract including the stomach, the small intestine, and the colon. The presently available oral, osmotic devices seemingly lack an apparent ability to deliver a drug to a selected region. That is, they are made to deliver drugs to all regions of the gastrointestinal tract.
It will be appreciated by those versed in the oral dispensing art, in view of this presentation, that a critical and an urgent need exists for an osmotic device that can deliver a drug only to certain regions of the gastrointestinal tract. The need exists for an oral osmotic device that can deliver a drug to certain regions of the gastrointestinal tract comprising the stomach and the small intestine for topical use or for absorption in these regions. The need exists also for an osmotic device that delivers drug only for topical application and for drug absorption in the colon. Such an osmotic device delays the onset of drug delivery for a period of time for the osmotic system to reach the latter region.